We propose to study an important and complex mental health problem related to aging: delusional major depression (DMD). Geriatric DMD is commonly encountered among elderly patients requiring psychiatric admission and highly responsive to electroconvulsive therapy (ECT); however, the prognosis is poor, with frequent relapses and rehospitalizations. Systematically obtained data on the course of DMD under conditions of intensive post-remission pharmacotherapy are not available. We will study 86 DMD's who have responded to ECT to compare the benefits and adverse consequences of vigorous pharmacotherapy with an antidepressant (AD) + antipsychotic (AP) during the six months using an AD alone. We will then compare the effectiveness of ongoing (maintenance) AD treatment with a placebo condition for up to two years. This approach will provide information of critical importance to clinicians about the course of DMD. These include: identifying periods of greatest risk for relapse/recurrence; determining the effectiveness and risks of continuing AP's after hospital discharge; and assessing the benefits and adverse events associated with maintaining elderly patients on therapeutic plasma levels of AD's beyond the first six months of continuation treatment. We will analyze our data to determine the contribution of important risk factors, particularly frequency of previous episodes and residual depressive symptoms to course of illness. We will also examine the relationship between failure to respond to pre- ECT intensive pharmacotherapy and course. Data analysis will utilize survival analysis techniques to determine time to relapse/recurrence under different treatment conditions.